ABSTRACT
<p><b>OBJECTIVE</b>To investigate changes of autophagy after traumatic brain injury (TBI) and its possible role.</p><p><b>METHODS</b>Rat TBI model was established by controlled cortical injury system. Autophagic double membrane structure was detected by transmission electronic microscope. Microtubule-associated protein 1 light chain 3 (LC3) and Beclin 1 were also used to investigate the activation of autophagy post-TBI. Double labeling with LC3 and caspase-3, or Beclin 1 and Fluoro-Jade to show the relationship between autophagy and apoptosis or neuron degeneration after TBI.</p><p><b>RESULTS</b>An increase of autophagic double membrane structure was observed in early stage (1 h), and the increase lasted for at least 32 d post-TBI. LC3 and Beclin 1 proteins also began to elevate at 1 h time point post-TBI in neurons, 3 d later in astrocytes, and peaked at about 8 d post-TBI. In both cell types, LC3 and Beclin 1 maintained at a high level until 32 d post-TBI. Most LC3 and Beclin 1 positive cells were near the side (including hippocampus), but not in the core of the injury. In addition, in the periphery of the injury site, not all caspase-3 positive (+) cells merged with LC3 (+) cells post-TBI; In hippocampal area, almost all Beclin 1 (+) neurons did not merge with Fluoro-Jade (+) neurons from 1 h to 48 h post-TBI.</p><p><b>CONCLUSION</b>Autophagy is activated and might protect neurons from degeneration at early stage post-TBI and play a continuous role afterwards in eliminating aberrant cell components.</p>
Subject(s)
Animals , Male , Rats , Apoptosis Regulatory Proteins , Metabolism , Astrocytes , Metabolism , Pathology , Autophagy , Beclin-1 , Brain , Metabolism , Pathology , Brain Injuries , Metabolism , Pathology , Caspase 3 , Metabolism , Cell Membrane , Metabolism , Pathology , Cytoprotection , Disease Models, Animal , Fluoresceins , Fluorescent Antibody Technique , Hippocampus , Metabolism , Pathology , Microscopy, Electron, Transmission , Microtubule-Associated Proteins , Metabolism , Nerve Degeneration , Metabolism , Pathology , Neurons , Metabolism , Pathology , Organic Chemicals , Rats, Sprague-Dawley , Time Factors , Up-RegulationABSTRACT
OBJECTIVE@#To study the expression of cathepsin-B and -D in different time point after traumatic brain injury.@*METHODS@#Traumatic brain injury (TBI) model was established on rats, cathepsin-B and cathepsin-D immunofluorescence staining and confocal microscope analysis were performed. Positive cells were counted by confocal microscope and image analysis techniques were used to determine the morphological changes in each group.@*RESULTS@#Immunofluorescence staining results showed that cathepsin-B was activated 1 hour after TBI while cathepsin-D was not activated until 12hour after TBI. Both of them got to their peak during 4 to 8days, and kept a high level of activating 32days after TBI. Cathepsin-B and -D positive cells did not merge with caspase-3 positive cells until 6 h after TBI.@*CONCLUSION@#Cathepsin-B and -D could be the diagnostic markers of TBI and can estimating time course of lateral TBI. They blocked caspase-3 activation at the beginning period after TBI and started to promote cell death with caspase-3 6 h after TBI.